2002 BMW 528I seats

5
Central Body Electronics ZKE III
The ZKE III system offers an overall reduction in vehicle wiring particularly in the areas sub-
ject to wear from movement such as doors, seats and the steering column. To accomplish
this, the “P- Bus” is used to interface (signaling) with peripheral modules over a single wire.
The ZKE III modular system consisting of the following components:
• General Module III = Main controller for ZKE functions
• PM - SB/FT = Driver’s door switch block and door module
• PM - BT = Passenger’s door module
• PM - SHD =Sunroof module
•PM - SM =Seat/Mirror/Steering Column memory module
• AIC = Rain Sensor (if equipped)
All modules communicate through the P-Bus and GM III onto the K-Bus for diagnosis.
PM-FT/SB
PM-SMPM-BT
PM-SHD
P-BUS
K-BUS
Driver's Door
Switchblock/
ModuleDriver's Door
Switchblock/
Module
Seat Memory
ModuleSeat Memory
Module
Passenger's
Door ModulePassenger's
Door Module
Sunroof
ModuleSunroof
Module
GM IIIFBZVFBZVDWADWA
FBZV
RECEIVER
MODULE
GM III MODULE
LOCATED IN CARRIER
FORWARD OF GLOVE BOX
Separate
Switch and
Module < 96
E38 on K-Bus
>99 MY
12520102.eps

Seat/Mirror/Steering Column Memory
Purpose of the System
The front seats, outside rearview mirrors and steering column (if equipped) positions are
electrically adjustable. The “customized” adjustment positions can be memorized and
stored for three diferent users and recalled back to the individual positions (with the excep-
tion of the passenger seat - not in memory).
The basic features of seat/mirror/steering column operation, as well as the memory posi-
tions is integrated into the ZKE III system.
• Seat/Steering Column Memory
Module (PM SM).
• Driver’s Door Switchblock Mod-
ule (PM FT/SB - early E38 was
separate).
• Passenger’s Door Module (PM
BT - E53 combined with window
switch).
• General Module (GM III).
• 3 Position Memory Switch.
• Seat Switch.
• Steering Column Switch.
• Seat/Steering Column/Mirror
Motors.
The Seat/Steering Column Memory Module communicates with the DISplus or MoDiC for
diagnosis and Vehicle Memory encoding.
58
Central Body Electronics ZKE III
System Components: Inputs - Processing - Outputs
E38/E39 Shown

Comfort Seats (standard on E38 750iL, other models if equipped)
This option provides additional back support in the
shoulder area. An additional adjustment in the upper
backrest allows forward “contour” that is controlled by
a rocker switch in the side panel.
When the ignition is on or off, the two way rocker switch
can be pushed until the desired setting is achieved (for-
ward/backward tilt). The motor drive operates the same
as the seat motors.
The shoulder support adjustment is also stored in
memory for recall.
Active Seat (E38 - if equipped)
Purpose of the System
Actively changing the surface of the seat helps to prevent muscle tension and fatigue par-
ticularly on long trips or sitting in one position for a long period of time. The seat causes
weight transfers which are slight and imperceptible enhancing driving comfort. The basic
seating position is not changed by this.
In the seat’s upholstery beneath the surface of the seat is a cushion of fluid on the left and
right. The fluid is slowly circulated back and forth between the cushions by a pump.
65
Central Body Electronics ZKE III

Principle of Operation
To activate this feature, the ignition must be in
the KL R or KL 15 and press the switch located
in the Center Console Switch Center (driver and/
or passenger front seat).
The switch provides a ground to the control
module and an LED in the switch will illuminate.
If there is a fault in the system the LED will not
illuminate.
The control module, fluid bladders (2 and 3) and
pump (1) is contained in each seat. The pump
contains a Hall sensor to monitor the number
motor revolutions and two pressure sensors to
monitor each bladder for vacuum (indicating
empty).
The fluid bladders (2 per seat) contain water-
glysantin mixture and are connected to the fluid
pump. The fluid bladders are equal in volume at
rest (15 mm. high) and will raise from 0 up 30
mm. when filled alternately from left to right.
Note: The pump unit and fluid bladders are replaced as a unit.
The control modules (one per seat) are connected to the P-Bus. The driver’s side control
module contains an acceleration sensor that monitors transverse acceleration of the vehi-
cle. Active Seat operation is temporarily interrupted during high acceleration.
Rear Power Seat (E38 750iL)
The rear seats in the 750iL provide electric adjustments for:
1. Backrest Angle - Control switch powers the motor.
2. Headrest Height - Control module behind each upper seat.
3. Lumbar Support
The headrest automatically extends when a passenger fastens
the safety belt and will automatically retract when the safety
belt is released. The power rear seat is a purely electric control
system. No electronic diagnostic communication is possible.
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Central Body Electronics ZKE III